Recharge

Recharge, alternatively cooldown or CD, is the interval of time (in seconds) after a skill or ability has been used before it can be used again. While a skill is recharging, its icon is darkened and has a clock-like animation that gradually brightens the icon until the skill has fully recharged. When an ability—such as the weapon set switch—is recharging, a white bar appears above the ability icon that depletes over time until the ability has fully recharged.

Skills have various recharge times. Some, such as Necrotic Bite, don't have any recharge at all and can be used again immediately. While a skill is recharging, it cannot be removed from your skill bar or replaced by another skill (excluding weapon skills when changing weapon sets). This is especially important to remember when using elite skills, as they can take up to 3 minutes to recharge. Before you can use the skill again or swap it for another, it must fully recharge.[1]

Weapon skills recharge even if their respective weapon set is not active.

When an effect description states that skills recharge X% faster, it seems to actually reduce the recharge time by X% instead. Thus, for example, a skill that "recharges 20% faster" can actually be used 25% more often (ignoring activation time).

Certain Sigils and Runes with active effects also have hidden recharge timers. The time taken to recharge can be found on the item, but there is no way to know exactly how long is left before it can activate again.